Photoperiod and temperature influences on growth in juvenile Atlantic salmon,Salmo salar L.
Adams, C.E.; Thorpe, J.E. (1989). Photoperiod and temperature influences on growth in juvenile Atlantic salmon,Salmo salar L., in: De Pauw, N. et al. (Ed.) Aquaculture: a biotechnology in progress: volume 1. pp. 797-799
In: De Pauw, N. et al. (1989). Aquaculture: a biotechnology in progress: volume 1. European Aquaculture Society: Bredene. ISBN 90-71625-03-6. 1-592 pp., more
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Document type: Conference paper
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| Abstract |
As with maturation. photoperiod regulates growth in salmonids. From a single pairing of Atlantic salmon 5 000 eggs were incubated in two groups, a standard under ambient water temperatures and an accelerated group at 10°C at the Almondbank experimental hatchery, Scotland. At the first feeding each group was divided into five populations of 400, and reared under controlled photoperiod regimes. One was exposed to constant conditions of 12L:12D, and reared under ambient water temperatures. Two were exposed to simulated natural photoperiod conditions with a starting date equivalent to February 1st, and two with a starting date equivalent to May 1st. One tank of each of these pairs received additional heat, 2°C above ambient in the standard group and 5°C above in the accelerated group, to a maximum of 20°C. Growth was monitored 192 days after the first feeding, when within the groups all four tanks had received the same total hours of light. The February-start populations had experienced 140 days of increasing followed by 52 days of decreasing daylength, and the others the complementary pattern of 52 increasing and 140 decreasing days. The greater the growth opportunity (°C x daylength hours) in late summer, especially July, the greater the proportion of young salmon populations that maintained rather than arrested growth. Virtually no potential S1s were produced under constant 12L:12D conditions, and mean lengths of these fish were less than under the varying photoperiod regimes. |
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